1. Field of the Invention
The present invention relates to a foldable container.
2. Description of the Related Art
A foldable container has been well known, in which a side plate corresponding to a long side is mounted rotatably on each of long sides that are opposed to each other of a rectangular bottom plate and a side plate corresponding to a short side is mounted rotatably on each of short sides that are opposed to each other of the bottom plate. For example, Japanese Utility Model Laid-Open No. 63-117725 has disclosed this kind of foldable container. The foldable container disclosed in the Japanese Utility Model Application Laid-Open No. 63-117725 comprises, as shown in FIGS. 15A and 15B, side plates 2 on the long side mounted rotatably onto the long sides that are opposed to each other of a rectangular bottom plate and side plates 3 on the short side mounted rotatably on the short side that are opposed to each other. As shown in FIG. 15B, a pair of the side plates 2 on the long side are fallen onto a pair of the side plates 3 on the short side and as shown in FIG. 15A, after raising the pair of the side plates 2 on the long side, a pair of the side plates 3 on the short side are raised and then, the side plate 3 on the short side is brought into contact with supporting protrusions 4 provided on both ends of the side plate 2 on the long side so as to prevent the side plates 3 on the short side from falling outward, thereby the foldable container being assembled in the form of a box.
When an individual carries the foldable container assembled in the form of box with a storage object therein usually the individual carriers it as if he or she embraces the container with the both hands with a long side of its rectangular shape opposing his breast. In this case, both hands of the individual carrying the foldable container press the side plates 3 of both the short sides that are opposed to each other inward as indicated by arrows in FIG. 15A. Consequently, there is a problem that when the individual carries the foldable container up/down or to other place with the hands, the side plates 3 may fall down. Although latching the side plates 3 with a latching hook freely releasable so as to prevent the side plates from falling inward, if an individual carries this foldable container assembled in the form of box with the both hands as if the individual embraces it as described above, the latching condition may be released by a force applied to the side plates 3 on the short side by the both hands, so that the side plates 3 on the short side may fall inward.
Because the side plate 3 on the short side may fall inward when the individual carries the foldable container assembled in the form of box, the storage object may be damaged by the side plated 3 on the short side that are fallen inward or he has to raise the side plate 3 on the short side again, which is a troublesome work.
Further, when the foldable container is folded down, the supporting protrusions 4, provided on both end portions of the side plate 2 on the long side for preventing the side plate 3 on the short side from falling down, protrudes downward from the side plate 2 on the long side, so that the stacking height of the folded container is increased by an amount corresponding to the length of the protrusion downward of the supporting protrusion 4. This is one reason why the foldable container is bulky when it is folded down.
If stacking height of the foldable container is large when it is folded down, distribution cost is increased, which is a problem to be solved.
It is an object of the present invention to provide a foldable container, wherein when an individual carries the foldable container assembled in the form of a box with the both hands as if he or she embraces it, the side plate on the short side never falls down even if it is pressed by the arm of the carrier, the foldable container capable of maintaining the assembled condition in the form of box securely and ensuring a low stacking height when it is folded down.
According to a first aspect of the present invention, there is provided a foldable container comprising a rectangular bottom plate, side plates on the long sides of the bottom plate mounted rotatably on the long sides that are opposed to each other and side plates on the short sides of the bottom plate mounted rotatably on the short sides that are opposed to each other, wherein the foldable container is folded by falling a pair of the side plates on the short sides onto a pair of the side plates on the long sides fallen down and the foldable container is assembled in the form of a box by raising a pair of the side plates on the short sides and then raising a pair of the side plates on the long sides. supporting protrusions are provided on part of both end portions on an inner face of the side plate on the short side, wherein the supporting protrusions support the both end portions of the side plate on the long side when the side plates on the short sides are raised so as to prevent the side plates on the long sides from falling outward. Further, the supporting protrusions are fitted into concave portions provided in both end portions on the long sides of the bottom plate when the side plates on the short sides are fallen. With such a structure, the both end portions on the inner face of the raised side plate on the short side are supported by the both side end faces of the opposing side plate on the long side, so that the side plate on the short side never falls inward until the side plate on the long side is fallen down. As a result, even if a force trying to fall the side plate on the short side inward is applied by an arm when an individual carries the foldable container assembled in the form of box as if he or she embraces it with the both hands, it is possible to prevent the side plates on the short sides from falling down. Further, when the side plates are raised, the both end portions of the side plate on the long side are supported by the supporting protrusions provided on part of the both end portions on the inner face of the side plate on the short side, so as to prevent the side plate on the long side from falling outward. Further, although the supporting protrusions are protruded downward from the side plate on the short side, the supporting protrusions are fitted into the concave portions provided in the both end portions on the long side of the bottom plate when the side plates are fallen down. Consequently, the stacking height when the foldable container is folded can be suppressed to be small.
Preferably, the supporting protrusions may be fitted into the concave portions and supported by the concave portions when the side plates on the short sides are fallen. With such a structure, when the container is folded down, a load applied to the side plate on the short side is supported by the supporting protrusions, so that the folded condition can be maintained stable.
Preferably, the concave portion may be formed of a hole open upward and having a bottom. If the concave portion has the bottom, the supporting protrusion fitted into the concave portion can be supported by the bottom of the concave portion. By fitting the supporting protrusion into the concave portion formed of a hole open upward, the supporting protrusion is not exposed on a side face of the foldable container when it is folded down, so that other object never collides with the supporting protrusion.
Preferably, the concave portion may be formed of a hole open upward and downward. With such a structure, even if there is provided a concave portion in which the supporting protrusion is to be fitted, it is possible to keep water from being deposited in the concave portion. By fitting the supporting protrusion into the concave portion formed of a hole open upward and downward, the supporting protrusion is not exposed on the side face of the foldable container when it is folded down, so that other object never collides with the supporting protrusion.
Further, preferably, when the side plates on the short sides in pairs are fallen, another portion than the portion on which the supporting protrusions are provided on each of both end portions of the side plate on the short side may be supported by both end portions on the long sides of the bottom plate with the supporting protrusions being fitted into the concave portions provided in the both end portions on the long side of the bottom plate. With such a structure, in the folded condition, a load applied to the side plate on the short side can be supported by the other portion than the supporting protrusion, so that the folded condition can be maintained stable.